1. Field of the Invention
This invention relates to a control apparatus for an embroidery sewing machine. More particularly, this invention relates to a control apparatus for an embroidery sewing machine of such a type that the moving direction of a movable frame is determined every time in order to trim a thread after the thread is cut to replace the thread in the course or upon completion of an embroidery sewing operation.
2. Description of the Related Art
Conventionally, a multi-needle embroidery sewing machine of a type including a single arm section or a plurality of arm sections is constructed such that a movable frame on which an embroidery frame or a plurality of embroidery frames to which a work fabric or fabrics to be embroidered are to be attached are mounted is supported for movement in an X-axis direction and a Y-axis direction. A needle bar change-over mechanism is provided such that a needle bar is changed over and a thread is cut by a thread cutting mechanism in accordance with embroidery data for each thread replacing operation so that a colorful embroidery can be sewn with a plurality of embroidery threads of different colors while driving the movable frame or frames to move.
By the way, for example, in a multi-needle embroidery sewing machine of a multi-head type, when a thread is cut by means of a thread cutting mechanism to replace the thread or when a thread is cut upon completion of an embroidery sewing operation, it is a common practice to perform thread trimming control. In order to simplify such thread trimming control, the movable frame is moved by a predetermined distance normally in a predetermined direction, for example, in the rightward direction or the leftward direction. Then, an end portion of the cut embroidery thread is trimmed from the work fabric, whereafter the movable frame is moved back by the predetermined distance in the opposite direction as disclosed in Japanese Patent Laid-Open No. 61-63762, published on Apr. 1, 1986.
As described above, in a multi-needle embroidery sewing machine, when a thread is cut and replaced or when an embroidery sewing operation is completed, the movable frame is moved normally in the predetermined direction to effect trimming of the thread. Accordingly, when the needle position in thread trimming is at or around a peripheral portion of an embroidery range of an embroidery frame on the trailing side of the predetermined direction, the movable frame cannot be moved by a distance necessary for thread trimming in the predetermined direction. Particularly, thread trimming is not performed with certainty after the thread is cut. Consequently, the conventional multi-needle embroidery sewing machine is disadvantageous in that sometimes an end portion of a preceding embroidery thread is sewn with a next embroidery thread.